This invention relates generally to an external drive assembly for use in automotive repair and maintenance, and more particularly, to an external drive assembly for rotating a disc brake rotor as part of an on-vehicle disc brake rotor resurfacing lathe assembly.
The maintainability of automobile disc brake assemblies has been enhanced by the use of on-vehicle portable brake rotor resurfacing lathes. One such on-vehicle disc brake lathe is shown at U.S. Pat. No. 4,854,199, assigned to the Assignee of the present application. Another such portable brake lathe is shown and described at U.S. Pat. No. 4,388,846. With such a lathe mounted on the brake caliper mounting bosses, the disc brake rotors may be resurfaced without removing them from their respective wheel hub assemblies. Such portable brake lathe assemblies provide for substantial space saving in repair facilities. Also, some wheel rotors are not removable without destroying wheel bearings. Stationary brake lathes have a tool feeding mechanism which provides for a constant tool feed speed when the object being machined is turned at a constant predetermined rotational speed. Except for all-wheel drive trucks and cars, present day motor vehicles have at least some wheels thereon which are not driven by the vehicle's engine. Therefore, there is a need for an external rotational drive source for use in connection with portable disc brake resurfacing lathes in order to drivingly rotate the rotors on the wheel assemblies which are not the driving wheels of the motor vehicle. Such external drive units should also be utilized with the driven wheels of the motor vehicle to impart a constant predetermined rotational speed to the rotors while resurfacing same. Such a constant rotational speed helps assure uniform machine finish across the rotor braking surface. Such a drive unit is shown in FIG. 3 of U.S. Pat. No. 4,336,730. That drive unit is shown to be stationary, and includes a pair of universal joints for providing adjustability between the electric motor output and the wheel hub assembly. The drive unit shown does not provide much flexibility in positioning the automobile wheel being worked on, and it also bisects, or divides into two, the area which the mechanic has available for working on the rotors.
A need has developed for a portable drive assembly that provides external rotational force to any one of a motor vehicle wheel assemblies for resurfacing a disc brake rotor thereon.
It is therefore an object of the present invention, generally stated, to provide a new and improved external drive assembly for use in connection with on-vehicle disc brake rotor resurfacers.